Apparatus for grinding plate-glass.



L. SPAGHTHOLZ 8: J. WINGERSON.

APPARATUS FOR GRINDING PLATE GLASS.

APPLICATION FILED M125. 1908.

916,935. Patented Mar. 30, 1909.

2 BKEBT8-BHEET 1.

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L. SPAGHTHOLZ & J. WINGERSON. APPARATUS FOR GRINDING PLATE GLASS.APPLIOLTIOH nun 1111.25. mos.

916,935. Patented Mar; 30.1909.

9 lHEBTB-BEBBT 2.

Invert/t0 rs UNITED s'rAtrns PATENT OFFICE.

LUDWIG SPAOHTHOLZ AND JOSEPH WINGERSON, 0F KITTANNING, PENNsY-LVANiA.APPARATUS FOR GRINDING PLATE-GLASS.

To all whom it may concern.

Be it known that we, LUDWIG SPAGIITHOLZ and JOSEPH WINoEnsoN, residentsof Kit tanning, in the county of Armstrong and State of Pennsylvania,have invented certain new and useful Improvements in Apparatus forGrinding Plate-Glass, of which the following is a specification.

This application is a division of our application filed December 14,1907, Serial No. 406,450, relating to grinding plate glass, and hasparticular reference to the apparatus therein disclosed.

One object is to provide mechanism for grinding several relatively smallplates while grinding a large plate or field. By preference, the area ofeach of the smaller plates is a fraction of the area of the large platesay approximately one-fourth, so that by applying two of the smallerplates at one time to the surface of the large plate, those two platesmay be ground while grinding the face of the lar e plate.

As further characteristic of the invention, a certain number of smallplates are roughground while rough-grinding thelarge plate, and then thesame small plates are smoothground while similarly grinding the largeplate. Thus, if the area ratio is 4 to 1, two of the small plates areapplied to the lar e plate and by the time they are complete yrough-ground about one-half of the process of roughrinding the largeplat-e has been accomplis red. The two small plates are then removed andtwo other unground plates substituted, and by the time the substitutedplates have been fully rough-ground, the rough-grindin of the largeplate has been completed. he smooth grinding of the plates may thenproceed without removing the last applied small plates until they havebeen smooth-ground and are ready for the final polishing. When this hasbeen accom- 'lished, the process of smooth-grinding the arge lates hasproceeded about one-half tows completion. The small plates that werefirst rough-ground are then substituted for the smooth-ground plates,and by the time the smooth-grinding of these substituted plates has beenaccomplished the smoothgrinding of the large plate has been completed.By this grinding one plate upon another, practically double the area isground as compared with the old practice of grinding a single surface bymeans of iron or other Specification of Letters Patent.

runner or grinding devices. in addition to increasing the out ut, theexpense of maintaining the runner "aces is wholly eliminated, and assuch runners wear uite rapidly the cost of keeping them in wor (ingcondition is considerable.

In practicing the invention, it is lmma terial whether driven, orpropelled ment with the large by a rotating table.

Apparatus embodying the improved devices is illustrated in theaccompanying drawings, Figure 1 being a side elevation thereof, partlyin section, one of the plate holders being shown raised. Fig. 2 is a topplan view of the table and plate holder's, one of the latter showing aclamping mechanism while only the top surface of the other detaohableplate holder head is shown. Fig. 3 is a vertical sectional view on alarger scale of one of the holders. Figs. 4 and 5 are detail views ofthe clamping device. Fig. 6 illustrates a modification of the operatinggearing.

Referring to the drawings, 2 desi .nates the large rotating tablesupported on t e central shaft or axle 3, the table and its rotatingmeans being of the usual well known construction.

4 designates a frame above the table, and in the embodiment hereillustrated two vertical shafts 5 are journaled therein, eccentric toshaft 3 and at equal distances therefrom, each carrying at its lower endthe four hori-- zontally radiatin arms 6.

7 designates t e plate holder heads. By preference each head is formedof cast iron, with its upper surface reinforced by circular flange 8 andthe four ribs 9 radiating from the center to the flange. The top facesof these ribs are flat like the under surfaces of arms 6 which registertherewith and bear thereon when the head is in position. For securingthe head, two clamping devices are preferably employed at opposite sidesof the center, the same being carried by two of the arms 6. Each deviceconsists of an inverted U-shaped yoke member 10 having its opposite armsslotted vertically at 11 to move on the transverse ins 12 in arm 6. Thelower extremities of t e yoke-arms are formed with hooks 13 t0 enga epins or lugs 14 projectin from opposite si es of ribs 9. The threadsstem 15, operating through the u per end of the yoke by means of handwheefit', raises the runners are positively solely by their engageplateordinarily carried and tightens the clamp with the hooks engaging lugs14. Two of these clamping devices operate to securely hold the head, andthey are of such construction and may be so manipulated that the headsmay be quickly and conveniently released. To accurately center the headsand hold them centered, each shaft 5 may be projected at 16 to enter acorresponding central depression 16 in the head, and a pin or lug 17 maybe similarly projected from each of arms 6 to enter a depres- 1 sion 17in each of ribs 9. The heads are prell erably square. For a table thirtyfeet in diameter each of the two heads may be 12 feet square. By sooperating the holders that the corners of one head approach the edges ofthe other head between its corners, there is no danger of collision,while at the same time their paths of movement so overlap as toeffectually o erate on the whole area of the table. For t us maintainingthe plate holders they may be cared together directly by wheels 18, asin ig. 2, and thus rotate in the same direction, or by interposing apinion 19 between gears 18, as in Fig. 6, they may be driven in reversedirections.

In operation, a plate or field of lass 20 is cemented on table 6 in theusual manner, while a plate 21 is similarly centered to the under faceof each head 7. With two of the holders in position, the rough-grindingproceeds, sand and water being applied as in the present practice. Ashere shown the holders are propelled by their contact with the table,but they may be positively driven. No novelty is claimed in thisconnection.

As the area of glass on the table is much larger than the combined areasof the two smaller plates, being double in the example here given, therough-grinding of the two small plates 21 is completed by the time therough-grinding of the large plate 20 is approximately one-half finished.At this stage the machine is stopped, and the two heads 7 carrying thefully rough-ground plates are removed and similar heads with freshplates are substituted for them. The operation then proceeds, and by thetime the substituted plates have been rough-ground, the rough-grindingof large plate 21 has been completed. The plates are then ready for thesmooth-grinding process in which a finer abrasive, such as emery, isused. This may proceed at once, the small plates last roughground beingthe first to be smooth-ground,

ence those plates are not removed from the machine from the time theyare first applied until after the whole grinding operation has beencompleted and they are ready for olishing. By the time these plates areully smooth-ground the same process has been a proximately one-halfcompleted as to the ar e late 21, and is fully completed alon wit t esmooth-grinding of the set of smafi plates which were firstrough-ground.

i pose being For connecting and. disconnecting heads 7, each o'l shai't5 may be ra sed and lowered in frame 4 by a lever 22. it will be noticedin this connection that the connectii'w ears are oi' such width thatthis vertical 11lovement of the shaft does not disengage them, and hencethe iositirming oi the small-plate holders with relation to each otheris always maintained.

lt will be understood that what we term the glass plate or field 21 ontable 2 is in practice. usually made up 01 a number ol plates of variousshapes and areas, the purto cover the table as fully as ossible. Thesame is true 0] the smaller plates. \Nhile some plates may be the exactsize of heads 7, it more often happens that their surfaces are coveredwith several plates. Hence, in referring to the small plates and to thelarge or table plate, we do not necessarily mean a single plate butrather a glass covered surface or field which may be made up of oneplate or several, according to circumstanees.

The method herein disclosed forms the subject matter of our abovementioned application for Letters Patent.

We claim 1. Plate glass grinding apparatus comprising a movable table, aplate of glass secured thereto, movable plate holders of equal sizeabove and smaller than the table, and plates of glass secured to theunder faces of the holders for hearing on the large plate secured to thetable.

'2. Plate glass grinding a paratus comprising a rotatable table, a 3 ateof glass secured thereto, two late hol ers of e ual size above the tableand equally spaced rom the center thereof with portions of the holdersmovable successively over said center, and plates of glass secured tothe under faces of the holders for bearing on the large plate secured tothe table.

3. Plate glass grinding a paratus comprising a rotatable table, a p ateof lass secured thereto, two square late ho ders of like size rotatablysupported above the table in diametrically opposite relation and atequal distances from the table center, the square holders being of suchsize that the corners thereof successively overlap the table center, andplates of glass secured to the holders for hearing on the plate securedto the table.

4. A plate holder for )late glass grinding machines comprising a ead, asup ortin shaft, arms radiating from the she. t, an means for detachablysecuring the head to said arms.

5. A plate holder for plate glass grinding machines comprising a head, arotatable supporting shaft, arms radiating from the she t, andadjustable clamping devices on the arms for detachably engaging thehead.

6. A plate holder for plate glass grinding machines comprising a headhaving radially arranged ribs on the upperaside thereof, a rotatablesupporting shaft, arms radiating from the shaft complementary with andadapted to bear against the ribs oi the hcml,

and means for securing together Sfllll arms and ribs.

7. A plate holder for plate glass grinding machines comprising a head,radially arranged ribs on the upper side thereof, a retatable sup ortingshaft, arms radiating from the slihft complementary with and adapted tobear upon said ribs, pins projecting from the ribs, and yoke-shapedclamps movably secured to the arms and provided with hooks for en agingthe pins on said ribs.

8. A plate hol er for plate glass grinding being slotted, a pinprojected through the slotted yoke and through the arm which the yokeembraces, and a screw adjustable in the yoke and adapted to bear uponthe arm.

In testimony whereof we affix our signatures in presence of twoWitnesses.

LUDWIG SPACHTHOLZ. JOS. WIN GERSON.

Witnesses R. L. RALSTON, MARY MCLAUGHLIN.

